What are the possible complications of euthyroid sick syndrome?

Complications depend on the underlying NTI and other organ systems involved. A study by Rothberger et al, for example, suggested that in patients with acute heart failure, low T3 levels due to euthyroid sick syndrome may be a risk factor for poorer hospital outcomes. The study found that in patients hospitalized with acute heart failure, those with low free T3 levels tended to have greater lengths of stay, higher rates of admission to the intensive care unit, and greater requirement for invasive mechanical ventilation.
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De Groot LJ. Non-thyroidal illness syndrome is a manifestation of hypothalamic-pituitary dysfunction, and in view of current evidence, should be treated with appropriate replacement therapies. Crit Care Clin. 2006 Jan. 22(1):57-86, vi. [Medline].